Limit invalidate calls for drawing compass in MyLocationOverlay

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Every time the compass gets a new bearing, the MyLocationOverlay throws a full 
invalidate() call. This happens often enough that it causes the maps to 
*constantly* redraw. This causes a constant high CPU usage.

I discuss this as a larger problem in Ticket 211, but the compass drawing is 
the worst offender and we really should fix that if nothing else.

Attached is a patch that does this. The patch works, but I'm a little shady on 
the calculations I used to get the invalidation area. I had to use 
trial-and-error and the mechanics seem reasonable, but I'm not particularly 
familiar with the combination of matrix operations used in the drawing for the 
compass so having someone validate it would be nice.

After a short period of review, I expect to commit this early next week.

Original issue reported on code.google.com by kurtzm...@gmail.com on 6 Apr 2012 at 7:42

• Blocking: #211

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Original comment by kurtzm...@gmail.com on 6 Apr 2012 at 7:42

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Patch attached.

Original comment by kurtzm...@gmail.com on 6 Apr 2012 at 7:47

Attachments:

• MyLocationOverlayCompassInvalidate.java.patch

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Sorry - to be clear, this patch will limit the compass's invalidate() call to 
just the dirty Rect, not the entire screen.

Original comment by kurtzm...@gmail.com on 6 Apr 2012 at 7:49

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This issue was closed by revision r1121.

Original comment by kurtzm...@gmail.com on 13 Sep 2012 at 9:15

• Changed state: Fixed